Speaking at Amazon’s European showcase, showrunner Gaiman explained: “I just remember the moment where I was half-way through writing episode three. Suddenly I had an idea for a scene which involves some physical comedy, and I thought, ‘I don’t know who could pull that off? That’s really difficult.’

“And suddenly I thought: ‘David Tennant could pull that off.’ And suddenly the way that I wrote Crowley from that moment changed.

“And I was absolutely certain and determined that David would be my Crowley.”

A demon who drives a vintage Bentley and eats in the finest restaurants, Crowley has become rather attached to Earth. His opposite number, the ever-lovely angel Aziraphale, is also reluctant to say goodbye to humanity and to his antiquarian bookshop in London.

As the Apocalypse looms, this unlikely duo will do everything they can to sabotage the coming of the end times.

Gaiman also revealed that Sheen initially had things the wrong way round – and thought he was being asked to play Crowley.

“Because I have known Michael for ages, I’ve known that Good Omens was one of his favourite books, I had a secret plan that I thought he would be really good,” Gaiman said.

“I sent him the scripts and said, ‘Can we meet for dinner?’ We met for dinner, he started saying – ‘I’ve read the scripts, I don’t really think that I’d be a good fit for Crowley. I’m not really sure that I can see myself as him.’

“And I said, ‘Yeah, well, I want you as Aziraphale.’ He was like: ‘What?'”

Gaiman added: “I think that came as something of a surprise to Michael, and it was a joy from that moment on.”